Thermite Well Severing Tool for Rig-Free Abandonment
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Solution Overview
Problem
Existing methods for abandoning offshore wells are costly and labor-intensive due to the need for multiple sequential steps to seal and remove tubular conduits, often requiring a rig derrick which adds significant expense, especially for subsea wells.
Innovation Solution
A method using a tool loaded with thermite and gas generating additives, such as covalent carbides, to sever tubing inside the well, allowing for a more efficient and cost-effective well abandonment process without the need for a rig derrick.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sequential sealing and removal methods are used for multiple conduits, then each conduit can be sealed and removed individually, but the number of operations becomes five times the number of conduits, significantly increasing time and cost
Solution Approach 1:
The patent combines multiple separate sealing operations into a single integrated sealing event. A packing tool is lowered into the wellbore and simultaneously seals multiple annular spaces between concentric conduits in one operation, rather than requiring separate sealing steps for each conduit interface. This merging of operations directly reduces the total number of steps from five times the number of conduits to a single operation.
Solution Approach 2:
The patent employs preliminary action by pre-positioning the packing tool with sealing elements at the required depth before activation. The tool is lowered into the wellbore and positioned at the target location, then activated to seal multiple annular spaces simultaneously. This preliminary positioning allows the sealing operation to be performed efficiently in a single event rather than requiring multiple sequential approaches.
2Ease of operation
If a rig derrick is installed or positioned for well abandonment, then the well abandonment procedure can be performed, but considerable expense is added to the task, especially for subsea wells
Solution Approach 1:
The patent enables the well abandonment procedure to be performed using existing wellbore equipment and tools without requiring external rig derrick support. The packing tool and severing tool are lowered into the wellbore via the existing conduit system and perform the sealing and cutting operations independently, utilizing the wellbore's own structural elements rather than requiring external rig infrastructure.
Solution Approach 2:
The patent extracts the essential abandonment functions (sealing and cutting) from the traditional rig derrick-based process and implements them through self-contained tools that can be lowered into the wellbore. The packing tool with its sealing elements and the severing tool with thermite charges are extracted as independent, movable units that perform the required operations without requiring the fixed infrastructure of a rig derrick.
3Reliability
If multiple sequential steps are used to seal and remove conduits, then each conduit can be handled separately, but the time taken and resources required at the well head increase considerably
Solution Approach 1:
The patent merges multiple sequential sealing operations into a single simultaneous sealing event. The packing tool is designed with multiple sealing elements that can engage and seal multiple annular spaces between different conduits at the same time, reducing the total abandonment time from multiple sequential steps to a single operation.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining pressure differential and sealing integrity throughout the simultaneous sealing operation. The packing tool is designed to seal all annular spaces continuously as it is lowered into the wellbore, ensuring that the sealing action is uninterrupted and efficient, rather than requiring multiple discrete steps with potential interruptions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method significantly reduces the number of operations required for well abandonment, thereby lowering costs and enhancing efficiency, while also eliminating the need for a rig derrick, particularly beneficial for subsea wells.
Implementation Method 1
A method of abandoning a well, by using a tool loaded with thermite and gas generating additive such as covalent carbides, such as silicon carbide and boron carbide
Implementation Method 2
thermite and gas generating additive such as covalent carbides, such as silicon carbide and boron carbide
Data Source
AI summary
A well cutting tool, comprising a housing including a chamber, the housing having at least one nozzle, the chamber being loaded with thermite, and a gas-generating additive an ignitor such that when the ignitor is actuated to ignite the thermite, the gas-generating additive is caused to create an increase in pressure which discharges energised molten thermite from the chamber and out of the housing through the at least one nozzle.